Technical Field
This disclosure relates to a sheet conveying device and an image forming apparatus incorporating the sheet conveying device.
Related Art
Various types of electrophotographic image forming apparatuses are known, including copiers, printers, facsimile machines, or multifunction machines having two or more functions of copying, printing, scanning, facsimile, plotter, and other capabilities. Such image forming apparatuses usually correct positional shifts with an inclination (skew) of a recording medium with respect to a sheet conveying direction in a sheet conveying path and simultaneously with a lateral shift or deviation of the recording medium in a width direction, which is a direction perpendicular to the sheet conveying direction, so as to adjust the recording medium to a normal position. (Hereinafter, the correction of the recording medium in the width direction is also referred to a “lateral shift correction”.)
For example, when a recording medium is conveyed by a pair of conveying rollers in an image forming apparatus, a contact image sensor (CIS) detects a lateral shift or deviation of the recording medium in the width direction and a pair of skew detection sensors detects an inclination (skew) of the recording medium in the sheet conveying direction. A pair of sheet holding rollers is rotated about a shaft thereof and moved (shifted) in the width direction at the same time, so as to correct the positional shifts of the recording medium in these directions. After the positional shifts are corrected, the recording medium is further conveyed by a pair of timing rollers in a downstream direction for a transferring process.